LAUSR

Sanfilippo syndrome (MPS III) is a rare, degenerative disorder with no approved therapies. This study explored caregiver perceptions of the burden of Sanfilippo syndrome on the child and family, and meaningful benefits that are desired from a non-curative therapy. We used an innovative mixed-method approach with 25 caregivers (biological and step-parents) of children ages 4-36 years old from 17 U.S. states. We conducted three focus groups comprising three activities: (1) formative validity testing of a symptom/staging survey (not described here), (2) moderated exploration of burden and meaningful treatment benefit, and (3) best-worst scaling (BWS) activities to quantify the relative importance of twelve treatment benefits, which arose during activity 2 and thus varied across focus groups. Thematic analysis revealed common themes and the quantitative analysis used ‘best-worst’ scoring to prioritize meaningful benefits from most to least important. Caregivers’ experiences reflect uncertainty and distress related to progression and increased family burden with progressing symptoms. Participants expressed willingness to “try anything” to slow or stop progression. Meaningful benefits to the family included reducing risky and perceived aggressive/impulsive behaviors and improving ability to communicate needs and preferences. For their children, focus group 1 prioritized addressing communication (relative importance score=.50), pain (score=.35), and child unhappiness (score=.33) group 2 prioritized communication (score=.58), frustration (score=.33), and aggressive behavior (score=.31) and group 3 prioritized communication (score=.50), pain (score=.48), and sleep (score=.23). Caregivers reflected on the relevance of communication challenges across disease progression. Consistent with prior reports, most caregivers identified considerable burden. Modest treatment benefits to communication limitations and problematic behaviors would be highly valued, as would reduced pain-especially given caregiver uncertainty regarding the child’s pain experience. Our next steps include using these data to develop a larger BWS survey to prioritize meaningful treatment benefits across stages of MPS III progression. Funding: Cure Sanfilippo Foundation, BioMarin, Lysogene, Sobi, Orchard Therapeutics.